Ignition System - Electronic (Turbo): Operation

The ignitor receives input from the signal rotor and pick-up coil to trigger the ignition system. See Figure. When the Electronic Control Module (ECM) detects that the turbocharger is operating, it will activate the knock control system and turn on the "TURBO" light on the instrument panel.

The ignitor and knock controller has 2 major circuits - one acting as transistorized ignitor and the other as a knock controller. The ignitor and knock controller retards ignition timing based on engine speed and signals from the knock sensor and ECM. The ignitor and knock controller will retard timing up to 12 degrees.

Engine speed is detected automatically by the knock controller circuitry. The knock controller also has a built-in fail safe circuit. It will retard ignition timing by a preset value if the knock sensor fails, or a short or open circuit occurs in the output leads. The ignitor and knock controller are located on the left side fenderwell between the battery and shock tower. See Figure.